Impact ignition device



March 4, 1930. G. SCAGLIA 1,749,720

IMPA CT IGNITION DEVICE FiledMay 23, 1927 2 Sheets-Sheet l //v1/[/v70 Gregana Saag/m March 4, 1930. SCAGLIA IMPACT IGNITION DEVICE Filed May 23, 1927 2 Sheets-Sheet 2 /A/I/E/V 727/1 W, fi M m; a M W Z V I Q,

Patented Mar. 4, 1930 GREGORIO SCAGLIA, OF TURIN, ITALY, ASSIGNOR TO SOCIETA ITALIAN A ERNESTO BREDA, OF MILAN, ITALY, A COMPANY OF ITALY IMPACT IGNITION DEVICE Application filed May 23, 1927, Serial No. 193,590, and in Germany June 4, 1926.

The present invention relates to percussion ignition .or firing devices for projectiles, bombs and the like, and has for its object a device comprising two elements adapted to approach one another at the time of impact to produce ignition of a primer, said elements being carried respectively by a support member for floating movement in the body of the device and by a member adapted to move along said support member and bearing upon a guide surface having a shape able to cause the distance between the said two elements to decrease when the axis of said support and member is diverted from its central position.

In the annexed drawings Figure 1 is a diagrammatic section view showing the essential feature of the device according to this invention;

igure 2 is a central section of a device according to this invention as applied to a percussion fuse for projectiles;

Figure 3 is a transverse section on line 33 of Fig. 2;

Figure 4 is a central section of a construc tion of the present invention as applied to a hand bomb or grenade;

Figure 5 is a top plan view of the bomb shown in Fig. 4;

section of a modified construction;

Figure 7 is a partial fragmentary central section of a further modified construction and Figure 8 is a top plan view of Fig. 7.

In the diagrammatic view ofFigure 1, reference 1 designates a part of the device to which is assumed to be rigidly fastened a part 2 providing a concave surface. A tubular member-5 having a rounded hollow end pierced by a hole 29 is connected for floating motion with'said member 1 by means of a ball oint having its centre at O and formed, in the illustrated embodiment, by a screw 3 fastened in the member 1 and having a stem 3 smaller than and extending through hole 29, a spherical contact head nut 4 being fastened on said stem 3' within said hollow tubular member 5 to provide a spherical supporting member for the said member 5; a

' position with Figure 6 is a partial fragmentary central movements of the internal are in all cases definltely determined, because one of the masses can never move away from movement on the member 5, said mass having a bore 30 passed through by a tail or extension 7 of member 5, and

in the region of the mass 8 which lies opposite the striker6 I a seat for a primer 9 is provided. The back of said mass 8 is rounded and bears on the surface 2, which is a surface of revolution about the axis of the screw 3-3.

Of course the may be any preferred one, being only essential that the distance from the centre 0 shall decrease as from the summit of this surface 2 towards the edge thereof.

In this way the member 5 and the mass 8, which are held apart by a spring 10, are forced to approach one another whenever the axis of the member 5 assumes an inclined respect to an axis passing through the centre 0 of the joint andthrough the summit of the section 2. It follows that the striker 6 strikes the primer not only when the mass is driven directly, by inertia, against the member 1, along the direction of the axis of the system, but also when the heavy mass is caused, by inertia, to deviate from the axis of the system owing to a lateralsh'ock.

Owing to the described arrangement, the movable system the point where it is pivoted but can onl turn about the centre of articulation 0 while the mass 8 is compelled the more to approach this centre the more it is displaced from its central position.

Further "the sensitiveness of the device is improved because it comprises'a single mass and thus it is possible toreduce to a minimum the weight of the pivoted element and, consequently, to have light parts (giving rise to small fragments in the case of hand bombs) and light and deformable parts (so that im-. pact on the target will give rise to instant detonation) in the case of fuses for artillery projectiles.

The device according to this invention has profile or section of surface 2 the further very important advantage in its application to fuses for artillery projectiles, that the rear mass is supported while the frontal member is pivoted in a positive man- 5 her and therefore it is in condition to resist the pull due to inertia at thetime the shot is fired. I Y

The firing device described may be applied directly to form a fuse for artillery. projectiles by fixing the stem 3 to the front end of a shell 11 as shown in Figure 2, screwed on a base 12 shaped like the surface 2 shown in Figure 1 and mounted in the frontal opening of the projectile. The back of the mass 8 carrying the primer 9, bears on the surface 2 and has an opening 13 to allow the flame of the primer to reach the charge of the projectile.

The safety device is constituted by a plate 14, pivoted at 15 on the face of the mass 8 opposite the striker 6. This plate normally occupies the mouth of the primer seat and has, on one side, a'heavy block '16 which,

when the fuse is being carried about, is locked 5 by a screw 17 screwed into the member 11.

Consequently, when the screw 17 is removed the plate 14 will still be interposed between the striker 6 and the primer until centrifugal force acting on the block 16 during the projectile flight and overcoming the action of the fiat spring 18 frictionally engaging it, has caused plate 14 to turn about the pivot 15 and brought it into the position indicated in dotted lines in Figure 3. When the impact takes place there will result, in

the above described manner, an abrupt'movement of primer 9 towards the striker and thus the fuse will be caused to act. I r It is to be remarked that a pin 19 fastened 40 to the stationary member 11, engages with radial play a .hole 31 of the member 5 and prevents the latter from rotating with respect to shell 11; for a similar purpose the extension 7 of member 5 has a projection 20 engaging a groove 32 formed in the mass 8.

The described safety device permits of the maximum degree of proximity between the striker and the primer and consequently makes the device highly sensitive to impact. Furthermore, as the plate 14 practically covers the primer, this latter cannot be prematurely struck by the striker, so that absolute safety is ensured during transport and at the firing of the shot, until the plate 14 has been moved away the action of centrifugal force, during the ht.

Figures 4 and 5 s ow the embodiment of the described ignition device to hand bombs. In said construction the heavy mass is provided with an explosive charge 33 enclosed in a casing 8' having a rounded bottom which bears on the surface of a jacket 18 which may be open at its bottom and is shaped to conform to the surface 2 of Figure 1. The jacket is completed by another, member 19 fixed to the jacket 18' by a bayonet joint and to which is pivoted by a ball joint 20, a striker 6 carrying the tubular member 5'.

Within said member 5 is mounted to slide a tube 21 carrying the primer 9 and detonator 34, this tube being solid with casing 8'.

A spring 10 holds the casing 8 normally'in its outermost position by pressing it against the inner surface of the jacket 18.

The safety device is constituted by a metal band'22 which is placed between the striker 6 and the primer, it extending freely throughout two diametrically opposite holes of jacket 19. This band is pivoted at one end to a cap 23 which fits on to the jacket 19 and also covers up the end of the band. A pin 24 provided with a finger ring 25, traverses cor responding holes in the cap 23 and jacket 19'.

Before throwing the bomb, the pin 24 is removed by acting on the finger ring 25 and when the bomb is thrown, the cap 23 being free to turn on its pivot, becomes reversed during flight through the air; then it is able to fall down free from the device and in so falling by gravity it withdraws the bar 22.

Consequently the striker is left directly facing the primer and their approach is brought about at the moment of impact whatever be the position in which the bomb comes into contact with the target.

If the impact takes place on the side of the portion 19' of the jacket, the mass 8 will be driven by inertia against the striker. If the impact takes place laterally, the relative ap proach of the striker and the primer takes place by the action of the surface 2 on the back of the casing 8'. Finally the explosion of the bomb is assured whether the impact takes place on the side of the part 18' of the jacket or the casing 8' strikes directly against the target and is driven against the striker or even if the bomb simply lays on one side, in which case the approach of the rimer towards'the striker is brought about by the action of the surface 2.

The construction shown in Fi re 6 differs from that. shown in Figures 4 an 5 only in so far as concerns the mounting of the oscillating member, which corresponds to that in Figure 2, and in the manner in which the band 22 is connected to the cap 23. i

In the case of Figures 7 and 8 the safety device is formed by a rod 22 inter osed between the striker and the primer an pivoted at one of its endsto a ring 26 formed to surround the body of the bomb and locked in this position by a pin 24 provided with a finger ring 25. In this case once the pin 24 has been withdrawn and the bomb thrown, the rin 26 separates, by reason of its weight, from t e bomb and thereby withdraws the rod 22'.

With this constructiomof bomb the advantage is secured that the heavy mass adapted to carry one of the elements of the ignition carried by very light members.

device is constituted by the explosive charge enclosed in a shell of sheet metal, while the other element of the said mechanism may be The bomb can, therefore, be constructed almost entirely of sheet metal which precludes the possibility of wide scattering and limits the radius of action of the bomb to a few feet only.

Finally the safety device described prevents the explosion of the bomb even if the jacket is crushed, since the striker is practically prevented from piercing the primer.

What I claim as my invention and desire to secure by United States Letters Patent 1s:-

1. An impact ignition device comprising a striker, a member carrying said striker, a primer, a second member carrying said primer, means interconnecting said members for respective movement with said striker and primer in aligned position, a supporting means for said members means connecting one of said members with said supporting part for oscillatory motion with respect thereto, with freedom of oscillatory motion with respect to said part, and means on said supporting part for efiecting movement of the other one of said members to approach the first mentioned member on said interconnected members being displaced from their central position with respect to said supporting part, said first mentioned member being of less weight than the other one of said members.

2. An impact ignition device comprising a striker, a member carrying said striker, a primer, a member carrying said primer, means interconnecting said members for respective movement with said striker and primer in aligned position, means enclosing said members, means connecting one of said members with said enclosing part for oscillatory motion with respect thereto, a striking body, and guiding means on said enclosing part to cause said striking body to move towards the first mentioned member on said interconnected members being displaced from their central position in said enclosing part.

3. Animpact ignition device comprising a striker, a primer, a striking body carrying said primer and having a greater weight than said striker, means interconnecting said striker and striking body for movement with relation to said striker and primer in aligned position, a part enclosing said striker and striking body, means connecting said striker and said enclosing part and permitting oscillatory movement of said body, and guiding means on said enclosing part to cause said striking body and primer to approach said striker on said interconnected striker and striking body being displaced from their aligned position in said enclosing part.

4. An impact ignition device comprising a striker, a member carrying said striker, a

= in a bore of the primer, a second member carrying said primer, an extension solid with one of said members and mounted to slide in a bore of the other member to hold said striker and primer in aligned position, a supporting part for said members, means connecting one of said interconnected members with said supporting part and permitting oscillatory movement of said body, and guiding means on said supporting part for causing the other member to approach said fioatingly bound member on said interconnected members being displaced from their central position in said supporting part.

5. An impact ignition device comprising a striker, a member carrying said striker, a primer, a member carrying said primer, an extension solid with one of said members and mounted to slide in a bore of the other one to hold said striker and primer in aligned position, a part enclosing said two members, means connecting oneof said members with said enclosing part, and permitting oscillatory movement of said member, the other one of said members providing a striking mass having a greater weight than said first mentioned member, and guiding means on said enclosing part to cause said striking mass to move towards said first mentioned member on said interconnected members being displaced from their central position in said enclosing part.

impact ignition device comprising a striker, a member carrying said strikerand having little weight, a primer, a striking body carrying said primer and having relatively great weight, an extension fixed with respect to one of said striker carrying members and striking body and arranged to slide other one to hold said striker and primer in aligned position, a part enclosing said striker carrying member and striking body, means connecting said striker carrying member with said enclosing part and permitting oscillatory movement of member with respect to the closing part, and guiding means on said enclosing part to cause said striking body to approach said striker carrying member on said interconnected striker carrying member and striking body being displaced from their central position in said enclosing part.

7. An impact ignition device comprising a striker, a member carrying said striker, a primer, a second member carrying said primer, means interconnecting said members for respective movement with said striker and primer in aligned position, a supporting part for said two members, means connecting one ofrsaid members with said supporting part for oscillatory movement with respect thereto, and means on said supporting part having a concave surface with its center beyond the center of said floatin 1y binding means to cause the other one 0 said members to approach the oscillatory member on said interconnected members being displaced from their central position in said enclosing part, said oscillatory member having light weight and the other one of said interconnecting members having a greater weight.

8. An' impact ignition device comprising a striker, a member carrying said striker, a

member and striking body being displacedfrom their central position in said enclosing part.'

9. An impact ignition device comprising a striker, a member carrying said striker, a primer, a second member carrying said primer, an extension solid with one of said members and mounted to slide in a bore of the other one to hold said striker and primer in aligned position, a supporting part for said members, means connecting one of said members with said supporting part for oscillatory movement with respect thereto, an

explosion charge embodied in the other one.

of said members, and guiding means on said supporting part to cause the last named one of said interconnected members to approach said oscillatory member on said interconnected members being displaced from their central position in said enclosing part.

10. An impact ignition device. comprising 'a striker, a member carrying said striker, a primer, a second member carrying said primer, means interconnecting said members for respective movement with said striker and primer in aligned position, a removable safety part intermediate said striker and primer, a supporting part for said members,

means connecting one of said members with said supporting part for oscillatory movement with respect thereto, means on said supporting part for causing the other one of said interconnected members to approach the said oscillatory member on said interconnected members being displaced from their central position in said 4 enclosing part, said oscillatory member being of light weight and the other one of said interconnected members being of greater weight. I

primer, means interconnecting sai 11. An impact ignition device comprising a striker, a member can 'ng said striker, a primer, a second mem er carr ng said members and guiding for respective mo. x nent with said striker and'primer in aligned positions, a removable safety part intermediate said striker and primer, a supporting part for said members connecting one of said members for oscillatory movement with respect to said supporting part, guiding means on said supporting part for causing the other one of said interconnected members to approach the said oscillatory member on said interconnected members being displaced from their central position in said enclosing part, said oscillatory member being light in weight and the other one of said interconnected members having greater weight, and a part removably arranged on said supporting part and connected with said safety part.

12. An impact ignition device comprising a striker, a member carrying said striker, a primer, :1. second member carrying said primer, means interconnecting said members for respective movement with said striker and primer in aligned position, a spring intermediate said members urging them away from each other, a supporting part for said members, means connecting one of said members with said supporting part for oscillatory movement with respect thereto, and

' guiding means on said supporting part for ca singflbe other one of said interconnected members to approach the said oscillatory member on said interconnected members being displaced from their central position in said supporting part, said oscillator member being light in weight and the other one of said interconnected members having greater weight.

13. 'An impact ignition device comprising a striker, a member carrying said striker, a primer, a member carrying said primer, means interconnecting said members for respective movement with said striker and primerin aligned position, a part enclosing said members and comprising a cap and a bottom part-assembled together, means for connecting one of said members with said cap for oscillatory movement with respect thereto, and guidin means on said bottom part to cause the ot er one of said interconnected members to approach said oscillatory member on said interconnected members being displaced from their central position within said assembled cap and bottom part, said oscillatory member being light in weight and the other one of said interconnected members having greater weight.

In testimony whereof I have signed my name to this specification.

. GREGORIO SCAGLIA. 

